If it is too slow it lowers efficiency. Too fast and it will cause erosion, vibration, and noise. It is best to keep the flow rate of your chiller somewhere between three and twelve feet per second. In most cases the chiller motor is the largest draw on electricity in the entire building.
Single speed drives are on or off and cannot adjust for the difference in load the system is running under. In contrast a variable speed drive saves energy as it can adjust the speed to match the load.
This saves a significant amount of energy in your chiller system. In addition variable speed allows the system to ramp up more smoothly in the case it is turned on in an emergency situation. If your compressor uses oil make sure you send a sample of it for inspection at a laboratory once per year.
Due to the hermetically sealed nature of a close refrigerant system the compressor oil should only be changed if the lab deems it necessary. If the oil is changed ensure the filters are tested and replaced when there are pressure drops. In the case your system uses magnetic bearings and is frictionless your system will not have compressor oil.
You can save energy and downtime if you inspect your motors and starters. To do so inspect the sensor calibration and safety on the microprocessor controls. Also take the time to inspect the wiring and connections in your chiller system at common wear points and hot spots. Pay attention to signs of refrigerant leaks and test motors for insulation faults. Chillers should be inspected and maintained at least 2 times a year in areas where they are only used during the cooling seasons, or 4 times a year in areas that cool in all 4 seasons.
Quarterly inspection helps your chillers, HVAC system, and cooling towers last longer and run more efficiently. Using this checklist you can get better performance out of your chiller and cooling system. The better maintained your chiller is the less energy it uses, and that saves you money on utilities.
As the chiller and HVAC system is one of the largest draws of electricity in many commercial, industrial, and medical facilities it is important to inspect, maintain, and repair chillers. Regular inspection and chiller maintenance will help save money and make the system last longer. If you have a property such as a commercial building, medical facility, or industrial site that uses chillers for processes or HVAC All Kote Lining, Inc can help you take care of the chiller maintenance you need to keep your energy use down and make your equipment last longer.
We inspect, maintain, repair, and line chillers with the most durable coatings available. Give us a call today to find out what we can do for your company at Save my name, email, and website in this browser for the next time I comment. Regular Post. Inspect water inlet and outlet for leaks Clean out and inspect the sump for corrosion Cooling coils need to be inspected and surfaces cleaned.
Check for leaks, corrosion, or bent fins The zone control actuators should be inspected, cleaned, and all adjustments made The compressor needs various areas checked, these include: refrigerant charge, vibration, crankcase heater, oil levels and changes, operating temperatures, and if there are any leaks of refrigerant or oil. Condenser fans should be cleaned, bearings need to be checked for wear and lubricated, and belts and couplings need to be checked and tightness checked or adjusted as necessary.
The condenser coil should be check for corrosion and leaks and all finds or combs need to be checked for bent sections.
The electrical disconnect should be inspected for proper operation and the contacts should be inspected and cleaned. The exhaust air damper needs to be inspected for proper operation, have the bearings lubricated, and calibrate or adjust it for optimal operation. Return air dampers also should be checked for proper operation, calibration, and bearings be lubricated. The fresh air damper should also be inspected, calibrated, and bearings lubricated. Capacities are tons and up.
The compressor requires no lubricant and has a variable-speed DC motor with direct-drive for the centrifugal compressor. Capacities range from 60 to tons. Because there are few absorption machines in the Northwest U. You can learn more about absorption chillers at the Energy Solutions Center. Key Components of Mechanical Compression Chillers Evaporator Chillers produce chilled water in the evaporator where cold refrigerant flows over the evaporator tube bundle.
The refrigerant evaporates changes into vapor as the heat is transferred from the water to the refrigerant. The chilled water passes through coils in the air-handler to remove heat from the air used to condition spaces throughout the building. The warm water warmed by the heat transferred from the building ventilation air returns to the evaporator and the cycle starts over. Compressor Vaporized refrigerant leaves the evaporator and travels to the compressor where it is mechanically compressed, and changed into a high-pressure, high-temperature vapor.
Upon leaving the compressor, the refrigerant enters the condenser side of the chiller. Condenser Inside the water-cooled condenser, hot refrigerant flows around the tubes containing the condenser-loop water.
The heat transfers to the water, causing the refrigerant to condense into liquid form. The condenser water is pumped from the condenser bundle to the cooling tower where heat is transferred from the water to the atmosphere. The liquid refrigerant then travels to the expansion valve. Expansion valve The refrigerant flows into the evaporator through the expansion valve or metering device.
This valve controls the rate of cooling. Once through the valve, the refrigerant expands to a lower pressure and a much lower temperature. Controls Newer chillers are controlled by sophisticated, on-board microprocessors. Chiller control systems include safety and operating controls.
If the equipment malfunctions, the safety control shuts the chiller down to prevent serious damage to the machine. Operating controls allow adjustments to some chiller operating parameters. Safety Issues Chillers are typically located in a mechanical equipment rooms. Each type of refrigerant used in a chiller compressor has specific safety requirements for leak detection and emergency ventilation. Consult your local mechanical code or the International Mechanical Code for details.
The EPA has enacted regulations regarding the use and handling of refrigerants to comply with the Clean Air Act of All personnel working with refrigerants covered by this act must be appropriately licensed. Best Practices for Efficient Operation The following best practices can improve chiller performance and reduce operating costs: Operate multiple chillers for peak efficiency: Plants with two or more chillers can save energy by matching the building loads to the most efficient combination of one or more chillers.
In general, the most efficient chiller should be first one used. Establish a chilled-water reset schedule. A reset schedule can typically adjust the chilled-water temperature as the outside-air temperature changes. The actual leaving tower water temperature may be limited by the ambient wet bulb temperature. Purge air from refrigerant: Air trapped in the refrigerant loop increases pressure at the compressor discharge.
This increases the work required from the compressor. Newer chillers have automatic air purgers that have run-time meters. Daily or weekly tracking of run time will show if a leak has developed that permits air to enter the system.
Optimize free cooling: If your system has a chiller bypass and heat exchanger, known as a water-side economizer, it should be used to serve process loads during the winter season. The water-side economizer produces chilled water without running the chiller. Condenser water circulates through the cooling tower to reject heat, and then goes to a heat exchanger bypassing the chiller where the water is cooled sufficiently to meet the cooling loads. Verify Performance of hot-gas bypass and unloader: These are most commonly found on reciprocating compressors to control capacity.
Make sure they operate properly. Both low-level and high-level refrigerant conditions can be detected this way. Taken together, these readings serve as a valuable baseline reference for operating the system and troubleshooting problems. Many newer chillers automatically save logs of these measurements in their on-board control system, which may be able to communicate directly with the DDC system.
Below is an example of a daily log that can be adapted for use with your chiller. Implementing a best-practice maintenance plan will save money over the life of the chiller and ensure longer chiller life. Substandard operating practices frequently go unnoticed and become the accepted norm. Training personnel in both maintenance and operating practices is the best prevention. Many chiller manufacturers offer training for building operating engineers in operating and maintaining their chillers.
To effectively maintain chillers, you must 1 bring the chiller to peak efficiency, and 2 maintain that peak efficiency. There are some basic steps that facilities professionals can take to make sure their chillers are being maintained properly.
Below are some of the key practices. Reduce Scale or Fouling Failure of the heat exchanger tubes is costly and disruptive. The evaporator and condenser tube bundles collect mineral and sludge deposits from the water. Scale buildup promotes corrosion that can lead to the failure of the tube wall. Scale buildup also insulates the tubes in the heat exchanger reducing the efficiency of the chiller. There are two main preventive actions: Checking water treatment: Checking the water treatment of the condenser-water open loop weekly will reduce the frequency of condenser tube cleaning and the possibility of a tube failure.
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